Air pollution and vulnerability: solving the puzzle of prioritization.

While ambient air pollution levels in excess of prescribed health standards are generally unacceptable, the exceedance is even more serious in areas where people reside. Vulnerability caused by poverty, disease, lack of education, and poor living conditions exacerbates the problem. Air quality management plans identify prioritized strategies for improved air quality independent of consideration of vulnerability. A population exposure and vulnerability risk prioritization framework comprising five themes (air pollution sources; air pollution levels; air pollution potential; community awareness, observations, perceptions, and actions; and vulnerability factors) was proposed and applied to the eThekwini Municipality (Durban, South Africa). Data were scored according to predetermined risk threshold values to ascertain at-risk communities. While those urban wards located in a known air pollution hotspot had the highest air pollution levels, a periurban ward with moderate exposure levels was most vulnerable. This framework will prove invaluable for the development of focused interventions to reduce vulnerability and air pollution-associated adverse health impacts.

Ultraviolet radiation exposure of children and adolescents in Durban, South Africa.

The solar ultraviolet radiation (UVR) exposure of 30 children and adolescents in three age groups (4-6 years, 7-9 years and 13-14 years) was measured for 1 week in late summer (February-March) in Durban, South Africa, using UVR-sensitive polysulfone film badges (PSFB) attached to the lapel region of the body. The mean and median values for all ages over the study period were 2.0 and 1.2 standard erythemal dose (SED) units, respectively, where 1 SED = 100 J x m(-2). Individual PSFB doses were analyzed as a function of age, gender and behavior. No significant statistical differences were found between different age groups; however, there was a statistical difference between males and females, with males generally receiving higher PSFB doses. Subjects completed UVR exposure journals documenting their time outdoors, shade versus sun conditions, nature of their activities, clothing worn and their use of sunscreen for each day of the study. Activity patterns were noted as the most important factor influencing individual UVR dose. Ambient erythemal UVR was measured by a Yankee Environmental Systems UVB pyranometer, and a relationship between ambient UVR and individual UVR dose was derived. On average, subjects received a dose of 4.6% of the total daily erythemal UVR. Based on this factor, the potential dose of an individual over a full annual cycle was estimated. Accordingly, there were 139 days during the year when an individual with skin type I (light skin) would be likely to experience minimal erythema and 97 and 32 days for individuals with skin types II and III, respectively.

Health risk assessment for sulfur dioxide pollution in South Durban, South Africa.

Concern about health risks from sulfur dioxide (SO2) pollution prompted a health risk assessment for residents of the heavily polluted industrial region of South Durban, South Africa. The U.S. Environmental Protection Agency health risk assessment model was used to evaluate health effects for individuals in 4 age groups on the basis of data for a 3-yr period, from 1997-1999. Under normal exposure conditions, the level of risk was low (Hazard Quotient < 1); only under the worst-case scenario (exposure 24 hr/day) was there a significant risk of developing health effects. Inasmuch as these results are contrary to the popularly held belief that residents have a high risk of developing SO2-related respiratory diseases under normal exposure conditions, future studies should more thoroughly investigate exposure patterns and verify the authors' assumption that indoor SO2 levels are zero.