Acid fog and hospital visits for asthma: an epidemiological study

Abstract

The aim of this study was to elucidate the adverse respiratory effects of naturally occurring acid fog. In total, 102 adult asthmatic patients (44 nonatopic and 58 atopic) were studied for a 2 yr period (January 1992 to December 1993) in Kushiro, a city with only a small industrial area, located in the northern-most island in Japan. Fog occurred on 378 out of 731 days, and the acidity of the fog ranged from pH 3.32 to 6.91 (mean pH 4.95). The association between hospital visits for asthma and meteorological factors or air pollutants was investigated. In nonatopic patients, fog, high ozone and water vapour pressure, low day-to-day temperature differences, low concentrations of atmospheric NO and NO2 contributed significantly (p<0.05) to increasing hospital visits. In atopic subjects, fog, high water vapour pressure, low levels of atmospheric NO2 and SO2 contributed significantly to hospital visits (p<0.05). In Poisson regression analysis the remaining factors of significance (p<0.01) for nonatopic asthma were fog and low NO and for atopic asthma were high water vapour pressure and low SO2 (p<0.05). A weak but significant correlation was observed between the number of hospital visits and the mean pH of the foggy day (r=-0.38, p<0.05) in nonatopic asthmatic patients, not in atopic asthma. On foggy days, gaseous air pollutant levels were significantly (p<0.01) lower than on fog-free days. It was concluded that, naturally occurring acid fog may have a weak bronchoconstrictive effect which appears to be more influential in nonatopic asthmatic subjects than in atopic subjects.

Correlation of light transmittance with asthma attack: fine water particles as a possible inducing factor of asthma

“…Ito et al [18] early in 1990s observed that emergency asthma visits in large hospitals were more frequent when temperature and vapor pressure (recorded by local meteorological observatories) were high, and that the observation was reproducible in two cities of different geographical locations in Japan. Similarly, Tanaka et al [19] found that naturally occurring acid fog increased hospital visits of adult asthmatic patients and that the fog effects were more evident among non-atopic asthmatics than among atopic patients. They added that gaseous air pollutant levels were lower on foggy days than on fog-free days.…”

A Persistent Fog Event Involving Heavy Pollutants in Yancheng Area of Jiangsu Province

“…ese activities are part of the core activities of modern societies, most notably aircraft operations, shipping [3], and road traffic [4]. Moreover, when the fog contains heavy pollutants, it is also harmful to human health [5]. is is why accurate forecasts of fog and haze have become an important issue.…”

Fogs: Physical Basis, Characteristic Properties, and Impacts on the Environment and Human Health

“…Air pollutants, such as nitrogen oxides ( NO x ), sulfur dioxides (SO 2 ), ozone (O 3 ), sulfuric acid (H 2 SO 4 ), and nitric acid (HNO 3 ), are among the constituents of acid fog; most of the fog acidity is attributable to the latter two [6]. The increase in respiratory mortality and morbidity, and of cardiopulmonary and lung cancer mortality is associated with exposure to fine aerial aerosol particles (in particular acidic ones), microbes, sulfur oxide and sulfur dioxide [6,7,100,101] (see Table 1).…”

“…The increase in respiratory mortality and morbidity, and of cardiopulmonary and lung cancer mortality is associated with exposure to fine aerial aerosol particles (in particular acidic ones), microbes, sulfur oxide and sulfur dioxide [6,7,100,101] (see Table 1). Table 1.…”

“…Tanaka et al [6] investigated the association between asthma-related hospital visits and meteorological factors or air pollutants. They studied 102 adult asthmatic patients (44 nonatopic and 58 atopic) in a period of two years.…”