Andrew Apsley

Secondhand smoke in cars: assessing children's potential exposure during typical journey conditions

Objective To measure levels of fine particulate matter in the rear passenger area of cars where smoking does and does not take place during typical real-life car journeys. Methods Fine particulate matter (PM2.5) was used as a marker of secondhand smoke and was measured and logged every minute of each car journey undertaken by smoking and non-smoking study participants. The monitoring instrument was located at breathing zone height in the rear seating area of each car. Participants were asked to carry out their normal driving and smoking behaviours over a 3-day period. Results 17 subjects (14 smokers) completed a total of 104 journeys (63 smoking journeys). Journeys averaged 27 min (range 5–70 min). PM2.5 levels averaged 85 and 7.4 μg/m3 during smoking and non-smoking car journeys, respectively. During smoking journeys, peak PM2.5 concentrations averaged 385 μg/m3, with one journey measuring over 880 μg/m3. PM2.5 concentrations were strongly linked to rate of smoking (cigarettes per minute). Use of forced ventilation and opening of car windows were very common during smoking journeys, but PM2.5 concentrations were still found to exceed WHO indoor air quality guidance (25 μg/m3) at some point in the measurement period during all smoking journeys. Conclusions PM2.5 concentrations in cars where smoking takes place are high and greatly exceed international indoor air quality guidance values. Children exposed to these levels of fine particulate are likely to suffer ill-health effects. There are increasing numbers of countries legislating against smoking in cars and such measures may be appropriate to prevent the exposure of children to these high levels of secondhand smoke.

An inexpensive particle monitor for smoker behaviour modification in homes

Objective To compare the response of a new particle counting instrument (Dylos DC1700) with that produced by a device (TSI Sidepak Personal Aerosol Monitor AM510) commonly used to measure PM2.5 in settings where secondhand smoke (SHS) is encountered. Methods Controlled chamber experiments with different SHS concentrations were generated by burning a cigarette for varying time periods and running both devices simultaneously. Results The Dylos and Sidepak devices produced similar responses to changes in SHS concentrations up to 1000 μg/m3. Using 591 min of contemporaneous measurements from 13 chamber experiments, an equation was developed to allow conversion of particle number concentration data from the Dylos to estimated mass concentration data for SHS aerosol. Conclusions The Dylos DC1700 can provide real-time data that may be converted to an estimate of SHS levels in smoky environments. Given the low cost, low noise and simplicity of use, this device is likely to be a useful tool for interventions to provide feedback of SHS concentrations to help motivate changes in smoking behaviour at home.

Using a new, low-cost air quality sensor to quantify second-hand smoke (SHS) levels in homes

Objective To determine if a low-cost particle counter, the Dylos DC 1700, can be used in homes to quantify second-hand smoke (SHS) concentrations. Methods Participants were recruited from a hospital-based study of attitudes on smoking. Two photometric devices (Dylos DC1700 and Sidepak AM510 Personal Aerosol Monitor) capable of measuring and logging concentrations of particulate matter were placed in smoking and non-smoking homes for approximately 24h. Acquired data were randomly allocated to one of two groups: one was used to generate a calibration equation using regression techniques; the second was used for validation of the generated model. The mean difference and limits of agreement between the two instruments were calculated using the validation dataset. Summary air-quality results were also compared across the entire dataset. Results Over 500 001 minute concentration measurements were collected from 34 homes. 25 301 randomly selected paired-measurements were used to generate a calibration equation (R2 0.86) converting the particle number concentration from the Dylos to a mass concentration of PM2.5 as measured by the Sidepak. The mean difference (limits of agreement) between the remaining 25 102 paired measurements was −0.09 (−49.7 to 49.5) with 3.2% of values outside the limits of agreement. Differences in the air quality information generated by the two instruments were generally small and unlikely to impact on user interpretation. Conclusions The Dylos appears to be a valid instrument for measuring PM2.5 in household settings. The Dylos may be useful in air quality-based interventions designed to change smokers’ behaviours with the possibility of encouraging cessation and/or smoke-free homes.

Fine particulate matter concentrations in smoking households: just how much secondhand smoke do you breathe in if you live with a smoker who smokes indoors?

Objective Using data on fine particulate matter less than 2.5 μm (PM2.5) concentrations in smoking and non-smoking homes in Scotland to estimate the mass of PM2.5 inhaled by different age groups. Methods Data from four linked studies, with real-time measurements of PM2.5 in homes, were combined with data on typical breathing rates and time-activity patterns. Monte Carlo modelling was used to estimate daily PM2.5 intake, the percentage of total PM2.5 inhaled within the home environment and the percentage reduction in daily intake that could be achieved by switching to a smoke-free home. Results Median (IQR) PM2.5 concentrations from 93 smoking homes were 31 (10–111) μg/m3 and 3 (2–6.5) μg/m3 for the 17 non-smoking homes. Non-smokers living with smokers typically have average PM2.5 exposure levels more than three times higher than the WHO guidance for annual exposure to PM2.5 (10 μg/m3). Conclusions Fine particulate pollution in Scottish homes where smoking is permitted is approximately 10 times higher than in non-smoking homes. Taken over a lifetime many non-smokers living with a smoker inhale a similar mass of PM2.5 as a non-smoker living in a heavily polluted city such as Beijing. Most non-smokers living in smoking households would experience reductions of over 70% in their daily inhaled PM2.5 intake if their home became smoke-free. The reduction is likely to be greatest for the very young and for older members of the population because they typically spend more time at home.

Secondhand smoke levels in Scottish bars 5 years on from the introduction of smoke-free legislation

Objective To determine current secondhand smoke (SHS) concentrations in bars previously assessed as part of an evaluation of Scottish smoke-free legislation 5 years ago. Design Comparison between SHS levels measured in 2006 and 2011 in 39 pubs in 2 Scottish cities. Methods Fine particulate matter (PM2.5) was measured discreetly for 30 min in each bar on one or two visits 5 years after the previous visit in May/June 2006. These 5-year follow-up visits were undertaken on the same day of the week and at approximately the same time of day. Results Average PM2.5 levels measured in a total of 51 bar visits in 2011 were 12 μg/m3 (range 2–155 μg/m3) compared to 20 μg/m3 (range 6–104 μg/m3) in the period immediately after the ban in 2006. Fine particulate concentrations in all but two visits in 2011 were comparable to PM2.5 levels measured in outside ambient air on the same day, with 92% of visits (n=47) providing 30-min average PM2.5 concentrations less than 25 μg/m3. Conclusions These results are one of the longest follow-up of any national smoke-free legislation and indicate that, 5 years after introduction, compliance is high and that the legislation continues to provide bar workers and non-smoking customers protection from SHS.

The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation ; part II : total inward leakage tests.

Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of respiratory protection (RP), most commonly surgical masks. However, there is currently no evidence on how effective such masks are in protecting wearers from volcanic ash. In Part I of this study (Mueller et al., 2018), we assessed the filtration efficiency (FE) of 17 materials from different forms of RP against volcanic ash and a surrogate, low-toxicity dust, Aloxite. Based on those results, we now present the findings from a volunteer simulation study to test the effect of facial fit through assessment of Total Inward Leakage (TIL). Four different disposable RP types that demonstrated very high median FE (≥96% for Aloxite; ≥89% for volcanic ash) were tested without provision of training on fit. These were an industry-certified mask (N95-equiv.); a surgical mask from Japan designed to filter PM2.5; a flat-fold basic mask from Indonesia; and a standard surgical mask from Mexico, which was also tested with an added medical bandage on top, as an additional intervention to improve fit. Ten volunteers (6 female, 4 male) were recruited. Each RP type was worn by volunteers under two different conditions simulating cleaning-up activities during/after volcanic ashfall. Each activity lasted 10 min and two repeats were completed for each RP type per activity. Dust (as PM2.5) concentration inside and outside the mask was measured with two TSI SidePak aerosol monitors (Models AM510 and AM520, TSI, Minnesota, USA) to calculate TIL. A questionnaire was administered after each test to collect perceptions of fit, comfort, protection and breathability. The best-performing RP type, across both activities, was the industry-certified N95-equiv. mask with 9% mean TIL. The standard surgical mask and the basic flat-fold mask both performed worst (35% TIL). With the additional bandage intervention, the surgical mask mean TIL improved to 24%. The PM2.5 surgical mask performed similarly, with 22% TIL. The N95-equiv. mask was perceived to provide the best protection, but was also perceived as being uncomfortable and more difficult to breathe through. This study provides a first objective evidence base for the effectiveness of a selection of RP types typically worn around the world during volcanic crises. The findings will help agencies to make informed decisions on the procurement and distribution of RP in future eruptions.

The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part I: Filtration efficiency tests

During volcanic eruptions and their aftermath, communities may be concerned about the impacts of inhaling volcanic ash. Access to effective respiratory protection (RP) is therefore important for many people in volcanic areas all over the world. However, evidence to support the use of effective RP during such crises is currently lacking. The aim of this study was to build the first evidence base on the effectiveness of common materials used to protect communities from ash inhalation in volcanic crises. We obtained 17 forms of RP, covering various types of cloth through to disposable masks (typically used in occupational settings), which communities are known to wear during volcanic crises. The RP materials were characterised and subjected to filtration efficiency (FE) tests, which were performed with three challenge dusts: ashes from Sakurajima (Japan) and Soufrière Hills (Montserrat) volcanoes and aluminium oxide (Aloxite), chosen as a low-toxicity surrogate dust of similar particle size distribution. FE tests were conducted at two concentrations (1.5 mg/m3 and 2.5 mg/m3) and two flow rates (equivalent to 40 and 80 l/min through 15.9 cm2 sections of each RP type). Each material was held in a sample holder and PM2.5 dust concentrations were measured both outside the mask material and inside the sample holder to determine FE. A limited number of tests were undertaken to assess the effect on FE of wetting a bandana and a surgical mask, as well as folding a bandana to provide multiple filter layers. Overall, four RP materials performed very well against volcanic ash, with median FEs in excess of 98% (N95-equiv., N99-equiv., PM2.5 surgical (Japan), and Basic flat-fold (Indonesia)). The two standard surgical masks tested had median FEs of 89-91%. All other materials had median FEs ranging from 23 to 76% with no cloth materials achieving >44%. Folding a bandana resulted in better FE (40%; 3× folded) than single-layered material (29%). Wetting the bandana and surgical mask material did not improve FE overall. This first evidence base on the FE of common materials used to protect communities in volcanic crises from ash inhalation has been extended in a companion study (Steinle et al., 2018) on the total inward leakage of the best-performing masks when worn by human volunteers. This will provide a complete assessment of the effectiveness of these RP types.

Effectiveness of face masks used to protect Beijing residents against particulate air pollution

Objectives Many residents in Beijing use disposable face masks in an attempt to protect their health from high particulate matter (PM) concentrations. Retail masks may be certified to local or international standards, but their real-life performance may not confer the exposure reduction potential that is marketed. This study aimed to evaluate the effectiveness of a range of face masks that are commercially available in China. Methods Nine masks claiming protection against fine PM (PM2.5) were purchased from consumer outlets in Beijing. The masks’ filtration efficiency was tested by drawing airborne diesel exhaust through a section of the material and measuring the PM2.5 and black carbon (BC) concentrations upstream and downstream of the filtering medium. Four masks were selected for testing on volunteers. Volunteers were exposed to diesel exhaust inside an experimental chamber while performing sedentary tasks and active tasks. BC concentrations were continuously monitored inside and outside the mask. Results The mean per cent penetration for each mask material ranged from 0.26% to 29%, depending on the flow rate and mask material. In the volunteer tests, the average total inward leakage (TIL) of BC ranged from 3% to 68% in the sedentary tests and from 7% to 66% in the active tests. Only one mask type tested showed an average TIL of less than 10%, under both test conditions. Conclusions Many commercially available face masks may not provide adequate protection, primarily due to poor facial fit. Our results indicate that further attention should be given to mask design and providing evidence-based guidance to consumers.

Domestic airborne fine particulate matter exposure and asthma control among children receiving inhaled steroid treatment

The aims of the present study were to measure domestic PM2.5 exposure and explore relationships with indices of asthma severity and control in children prescribed inhaled corticosteroids (ICSs). Disease severity was determined by questionnaire and spirometry. Asthma control was assessed by 5-day peak flow variability (PFV) and childrens asthma control test (CACT) on the 1st and 5th day of peak flow testing. Concentrations of PM2.5 were measured over a 24-h period. Twenty-two children were recruited, mean age 11.0 years. Across the 22 homes the median time weighted average (TWA) PM2.5 concentration (range) was 7.4 μg/m3 (2.0–150.0) and was significantly higher in the seven homes where smoking was reported (24.0 μg/m3) than non-smoking homes (6.0 μg/m3), p=0.001. There was a positive association between TWA PM2.5 and PFV (rho = 0.55, p = 0.015, n = 19) and a negative association between TWA PM2.5 and CACT (rho = − 0.56, p = 0.010, n = 20). TWA PM2.5 exposure was not related to indices of asthma severity. Peak PM2.5 concentration was not associated with any outcome. This exploratory study suggests that even at relatively low concentrations, there is an exposure–response relationship between increasing indoor air PM2.5 concentrations and poorer asthma control in children prescribed ICSs.

The UCB particle monitor: A tool for logging frequency of smoking and the intensity of second-hand smoke concentrations in the home

Second-hand tobacco smoke (SHS) exposure generates a large public health burden. Recent legislation has moved to prohibit smoking in public places and there are concerns that this may lead to an increase in exposures in private homes. Measurement of SHS aerosol has tended to use active pumped samples or longer-term diffusive badges. Pumped methods are noisy and poorly tolerated in home settings while diffusive badges do not provide real-time data. The UCB particle monitor (UCB-PM) is a modified smoke-alarm device capable of logging changes in airborne particulate matter over extended periods and has been used successfully to measure biomass fuel smoke concentrations in developing world settings This study has examined the use of the UCB-PM to measure SHS aerosol in both controlled laboratory conditions and a pilot field trial over a 7 day period in a smokers home. Comparisons with a pumped sampler (TSI Sidepak Personal Aerosol Monitor) indicate good agreement over a range of exposure concentrations but there is evidence of a threshold effect at approximately 0.5 mg/m3 of fine particulate measured as PM2.5. While this threshold effect undermines the ability of the device to provide useful data on the time-weighted average SHS concentration, the field trial indicates that that the UCB-PM has a sensitivity of about 71% and a specificity of 98%. The device has many advantages including zero noise operation, low cost and long battery life and may be a useful tool in quitting and smoke-free home intervention studies.