MONDAY, April 25, 2022 (HealthDay News) -- Short-term exposure to particulate matter (PM) and black carbon is associated with an increased risk for positive results on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) testing, according to a study published online April 20 in JAMA Network Open.
Zhebin Yu, Ph.D., from the Karolinska Institutet in Stockholm, and colleagues estimated the association between short-term exposure to ambient air pollution and SARS-CoV-2 infection among Swedish young adults. A total of 425 cases with positive results for SARS-CoV-2 PCR testing from May 5, 2020, to March 31, 2021, were identified. Case day was defined as the date of the PCR test, while control days were the same day of the week within the same calendar month and year.
The researchers found that on case days, the median exposure level for PM with diameter ≤2.5 μm (PM2.5) was 4.4 μg/m3; for PM with diameter ≤10 μm (PM10), the median exposure level was 7.7 μg/m3; for black carbon, it was 0.3 μg/m3; and for nitrogen oxides, it was 8.2 μg/m3. On control days, the corresponding median exposure levels were 3.8, 6.6, 0.2, and 7.7 μg/m3. Each interquartile range increase in short-term exposure to PM2.5 on lag 2 was associated with a 6.8 percent relative increase in positive results of SARS-CoV-2 PCR testing, while there were relative increases of 6.9 and 5.8 percent for exposure to PM10 on lag 2 and exposure to black carbon on lag 1, respectively; no association was seen with nitrogen oxides.
"These findings support the broad public health benefits of reducing ambient air pollution levels," the authors write.