Air pollution is a leading environmental risk factor for premature death globally. People are typically exposed to gaseous and particulate pollutants simultaneously in the real-world. People spend various time in different microenvironments, including home, office, transit, others and outdoor. Health risks caused by air pollution exposure differ among individuals due to differences in activity, microenvironmental concentration, as well as toxicity of pollutants. Most of the existing individual exposure studies were conducted on particulate matter (PM). Limited information is available on personal exposure variability for gaseous pollutants (i.e., NO
2 and O
3) due to complexity and difficulty in measuring those pollutants. Using added health risk (AR) model, we evaluated short-term health...[
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Air pollution is a leading environmental risk factor for premature death globally. People are typically exposed to gaseous and particulate pollutants simultaneously in the real-world. People spend various time in different microenvironments, including home, office, transit, others and outdoor. Health risks caused by air pollution exposure differ among individuals due to differences in activity, microenvironmental concentration, as well as toxicity of pollutants. Most of the existing individual exposure studies were conducted on particulate matter (PM). Limited information is available on personal exposure variability for gaseous pollutants (i.e., NO
2 and O
3) due to complexity and difficulty in measuring those pollutants. Using added health risk (AR) model, we evaluated short-term health risk of NO
2, O
3 and PM
2.5 based on ambient concentrations in urban areas with dense traffic and less urbanized areas. Although PM
2.5 has a significant long-term health risk, NO
2 and O
3 are more predominant in short-term health risk than PM
2.5. Thus, with the recent technological advancement, we measured real-world personal exposure to both gaseous and particulate pollutants using next generation sensors across 21 participants in their daily life. We quantified health risk of combined exposure to NO
2, O
3 and PM
2.5 using AR model. Inter-and intra-individual variability in health risks and sources of variations were investigated using linear mixed-effects models and correlation analysis, respectively. Daily time-integrated AR for combined NO
2, O
3 and PM
2.5 (TIAR
combine) ranged by a factor of 2.5 among participants and by a factor of 1.0 to 2.5 for a given person across measured days. Several factors were identified to be significantly correlated with daily TIAR
combine, with the top 5 factors including NO
2, O
3 and PM
2.5 concentrations at home, O
3 concentrations at office and ambient PM
2.5 concentrations. The results on the sources of variability in daily personal health risk are great potentials that could help in targeting interventions to reduce daily health damage related to air pollution.
Based on the results, participants were exposed to 64% of daily TIAR
combine at home. Infiltration of outdoor pollutants is an important source of people’s exposure at home. Thus, identifying sources that lead to variations in outdoor infiltration can help in targeting interventions to reduce home exposure. We measured simultaneous indoor and outdoor NO
2, O
3 and PM
2.5 concentrations using next generation sensors from 55 home campaigns to identify key factors affecting infiltration of gaseous and particulate pollutants. We identified key controllable sources of variability in infiltration factors (F
inf) in NO
2, O
3 and PM
2.5 using stepwise multiple linear regression. Ventilation practices (e.g., window opening duration and air-conditioning (AC) on/off) have significant impacts on outdoor infiltration of PM
2.5 and NO
2, accounting for 48% and 20% of the variations in F
inf, respectively. Use of air purifiers explained an additional 8%-9% of variations in F
inf for these two pollutants. For O
3, homes with AC on were significantly associated with lower infiltration than homes with AC off. Thus, people can reduce infiltrated ambient air pollution in the homes by changing their ventilation practices (e.g., window close and use of AC) and using air purifiers. It is recommended to close windows and turn on AC during high air pollution episodes to protect sensitive people (e.g., children, elderly, and people with underlying respiratory and cardiovascular diseases) from exposure to high pollution.
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