Association between chemical components of PM2.5 and children's primary care night-time visits due to asthma attacks: A case-crossover study

Publication date: Available online 7 February 2019

Source: Allergology International

Author(s): Shin Yamazaki, Masayuki Shima, Yoshiko Yoda, Fumitake Kurosaka, Toshio Isokawa, Shigeta Shimizu, Teruhiro Ogawa, Naohiro Kamiyoshi, Kunihiko Terada, Jittoku Nishikawa, Kenji Hanaoka, Taku Yamada, Shinro Matsuura, Akihiro Hongo, Ichiro Yamamoto

Abstract

Background

Few papers have examined the association between the chemical components of PM_2.5 and health effects. The existence of an association is now under discussion.

Methods

This case-crossover study aimed to examine the association between the chemical components of PM_2.5 and night-time primary care visits (PCVs) due to asthma attacks. The subjects were 1251 children aged 0–14 years who received medical care for asthma at a municipal emergency clinic. We measured daily average concentrations of hydrogen ion, sulfate ion, nitrate ion and water-soluble organic compounds (WSOCs), which are components of PM_2.5. We estimated the odds ratios (ORs) of PCVs per unit increment (inter quartile ranges) in each chemical component of PM_2.5 for the subgroups of warmer months and colder months separately.

Results

No association was seen between PCVs and PM_2.5 mass concentrations the day before the PCVs in either warmer or colder months. In the warmer months, an association was seen with the concentrations of WSOCs and hydrogen ion the day before the PCVs (OR = 1.33; 95% CI: 1.00–1.76, OR = 1.18; 95% CI: 1.02–1.36, respectively). Furthermore, a negative association was seen between sulfate ion and PCVs (OR = 0.85; 95%CI: 0.74–0.98). No associations were observed in the colder months.

Conclusions

We observed a positive association between PCVs and certain concentrations of WSOCs and hydrogen ions in warmer months. In contrast, sulfate ion showed a negative association.

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