The nexus between in-car aerosol concentrations, ventilation and the risk of respiratory infection

Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved..

We examined the trade-offs between in-car aerosol concentrations, ventilation and respiratory infection transmission under three ventilation settings: windows open (WO); windows closed with air-conditioning on ambient air mode (WC-AA); and windows closed with air-conditioning on recirculation (WC-RC). Forty-five runs, covering a total of 324 km distance on a 7.2-km looped route, were carried out three times a day (morning, afternoon, evening) to monitor aerosols (PM2.5; particulate matter < 2.5 μm and PNC; particle number concentration), CO2 and environmental conditions (temperature and relative humidity). Ideally, higher ventilation rates would give lower in-car pollutant concentrations due to dilution from outdoor air. However, in-car aerosol concentrations increased with ventilation (WO > WC-AA > WC-RC) due to the ingress of polluted outdoor air on urban routes. A clear trade-off, therefore, exists for the in-car air quality (icAQ) versus ventilation; for example, WC-RC showed the least aerosol concentrations (i.e. four-times lower compared with WO), but corresponded to elevated CO2 levels (i.e. five-times higher compared with WO) in 20 mins. We considered COVID-19 as an example of respiratory infection transmission. The probability of its transmission from an infected occupant in a five-seater car was estimated during different quanta generation rates (2-60.5 quanta hr-1) using the Wells-Riley model. In WO, the probability with 50%-efficient and without facemasks under normal speaking (9.4 quanta hr-1) varied only by upto 0.5%. It increased by 2-fold in WC-AA (<1.1%) and 10-fold in WC-RC (<5.2%) during a 20 mins trip. Therefore, a wise selection of ventilation settings is needed to balance in-car exposure in urban areas affected by outdoor air pollution and that by COVID-19 transmission. We also successfully developed and assessed the feasibility of using sensor units in static and dynamic environments to monitor icAQ and potentially infer COVID-19 transmission. Further research is required to develop automatic-alarm systems to help reduce both pollutant exposure and infection from respiratory COVID-19 transmission.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:157

Enthalten in:

Environment international - 157(2021) vom: 04. Dez., Seite 106814

Sprache:

Englisch

Beteiligte Personen:

Kumar, Prashant [VerfasserIn]
Omidvarborna, Hamid [VerfasserIn]
Tiwari, Arvind [VerfasserIn]
Morawska, Lidia [VerfasserIn]

Links:

Volltext

Themen:

Aerosols
Air Pollutants
COVID-19 transmission
Envilution® Chamber
In-car exposure
Journal Article
Low-cost sensors
Particulate Matter
Research Support, Non-U.S. Gov't
Respiratory infection
Transport microenvironments

Anmerkungen:

Date Completed 06.10.2021

Date Revised 06.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.envint.2021.106814

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM329552112