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Biomedical subjects

H H John

Publications and source records attributed to H H John.

10 recordsLinked to original sources
PubMed1995

A code of practice on dealing with infectious diseases on aircraft.

Increasing numbers of people are travelling to and from more distant destinations with the possibility of exposure to common as well as exotic disease. At the present time there are no readily accessible rules or guidance for dealing with possible cases of infectious disease occurring during international flights. A 'Code of Practice on dealing with infectious disease on aircraft' is proposed as a ready means of dealing with the problem without excessive action or expense.

Aircraft↗
PubMed1985

Investigations into the relations between respiratory illness in children, gas cooking and nitrogen dioxide in the U.K.

In 1977 an association was reported between the prevalence of respiratory illness and use of gas for cooking at home in a national sample of six to 11 year olds living in England and Scotland (p less than .10). Other variables such as social class and number of cigarette smokers at home did not seem to explain the association. As the gas cooker is an unflued appliance emitting a variety of pollutants during gas combustion it was suggested that indoor air pollution might explain the finding. Nitrogen dioxide (NO2) was suspected so a series of studies was conducted to investigate the distribution of levels of NO2 in the home, the relative contribution of sources of NO2 to indoor exposure and the relation between respiratory illness in six to 11 year olds and levels of NO2 in the home. The gas cooker was found to be one of the main sources of NO2 in the home. Winter weekly averages in kitchens with gas cookers had a mean of 112.2 ppb (n = 428, range 5-317 ppb). Levels in electric cooking kitchens were significantly lower (n = 87, mean 18 ppb, range 6-188 ppb). Studies of health indicated a relation between respiratory illness and bedroom levels of NO2 over the range 4-169 ppb (p .10). Results for living room levels of NO2 suggested a similar but non-significant relationship (p greater than .10). No relation was found for kitchen levels of NO2. For schoolchildren any effect on health from indoor NO2 is likely to be weak. However other sections of the population such as infants and the elderly who may spend more time indoors and are particularly susceptible to respiratory illness need to be studied to assess fully the impact that NO2 may be having on health.

Child↗
PubMed1982

Childhood respiratory illness and the home environment. I. Relations between nitrogen dioxide, temperature and relative humidity.

The relation between the use of gas for cooking, nitrogen dioxide (NO2), temperature and relative humidity was investigated in an urban area of northern England. In a pilot study conducted in a random sample of 40 homes measurements of temperature and relative humidity were not significantly different between homes with a gas cooker and homes with an electric cooker but weekly average levels of NO2 were higher in bedrooms (p less than 0.005) and living rooms (P less than 0.01) of gas homes. In the main study conducted in gas cooking homes only, access was gained to 183 (54.3%) of 337 randomly selected homes. No correlation was found in children's bedrooms between with weekly average level of NO2 (range 4.7 to 160.8 ppb) and weekly average temperature (ranged 7.7 to 22.0 degree C; r = 0.05, p greater than 0.10) or relative humidity (range 37.0 to 98.1%; r = 0.07, p greater than 0.10). Levels of NO2 in the bedroom were positively correlated with those in the living room (range 9.0 to 292.2 ppb; r = 0.39, p less than 0.01). Factors which tended to be associated with high levels of NO2 in the home included gas fires, paraffin heaters and use of the cooker for heating and drying clothes.

Air Pollutants↗
PubMed1982

Childhood respiratory illness and the home environment. II. Association between respiratory illness and nitrogen dioxide, temperature and relative humidity.

The relation of respiratory illness to nitrogen dioxide (NO2), temperature and relative humidity in homes with a gas cooker was investigated in five and six year old children living in an urban area of the northern England. NO2 was measured for one week in the child's bedroom and living room of each home, and temperature and relative humidity were measured in the bedroom only. Information on respiratory conditions experienced by the child and characteristics of the home was collected in a self-administered questionnaire completed by the child's mother. Access was gained to 183 homes (54.3% of 337) where only gas was used for cooking. Complete information was obtained for 179 (93.7%) of 191 children who lived in the 183 homes. After allowing for the effects of age, sex, social class, and number of cigarette smokers in the home and temperature or relative humidity, no statistically significant relation was found between the prevalence of having one or more respiratory conditions and weekly average levels of NO2 in the bedroom (range 4.7 to 160.8 ppb) or living room (range 9.0 to 292.2 ppb). However, the prevalence of having one or more respiratory conditions tended to be highest in homes with high levels of NO2 and lowest in homes with low levels, consistent with earlier findings. A significant positive association was found between the prevalence of respiratory conditions and relative humidity (p less than .05). A harmful effect on health from NO2 cannot be totally dismissed but if it exists it is weak and difficult to detect in small samples of children.

Air Pollutants↗
PubMed1982

The epidemiology of indoor nitrogen dioxide in the U.K.

The results of three studies on the effect of gas cooking on the lung function of children are reported. The studies which have been carried out in England and Scotland with children aged 6-11, 6-7 and 5-6 years, respectively, show that there is only a weak association between indoor levels of NO2 and respiratory illness. Nevertheless, the consistency of the difference in the rate of respiratory diseases in children from homes with electric and gas cookers suggest there is some hazard to the use of unflued gas appliances which may warrant further epidemiological investigation.

Child↗
PubMed1979

The relation between respiratory illness in primary schoolchildren and the use of gas for cooking--II. Factors affecting nitrogen dioxide levels in the home.

The study was designed to determine whether there was an association between indoor levels of nitrogen dioxide (NO2) and respiratory illness and lung function in schoolchildren. NO2 was measured for one week in the winter outside and inside the homes of children aged 6-7 years living and attending primary schools in a defined 4 square km area in Middlesbrough, Cleveland, UK. Outdoor levels of NO2 measured at 75 points within the area ranged from 14-24 ppb weekly average. Measurements were also made in 428 kitchens with gas cookers, range 5-317 ppb, mean 112.2 ppb, and in 87 kitchens with electric cookers, range 6-188 ppb, mean 18.0 ppb. In a random subsample of homes the range of NO2 levels in 107 children's bedrooms in homes where gas was used for cooking was 4-169 ppb, mean 30.5 ppb, in 18 bedrooms in electric cooking homes the range was 3-37 ppb, mean 13.9 ppb. NO2 levels in the gas cooking kitchens were positively related to the presence of pilot lights, use of gas fires for main heating, number of regular smokers, and the number of people in the home. Information from 29 homes with the highest kitchen NO2 levels paired with 29 low NO2 gas cooking homes showed that the daily number of meals eaten and the frequency with which the cooker was used for heating and drying clothes were significantly greater in the high NO2 homes.

Air Pollutants↗
PubMed1979

The relation between respiratory illness in primary schoolchildren and the use of gas for cooking--III. Nitrogen dioxide, respiratory illness and lung infection.

We examined the relation between lung function and respiratory illness in a population of 808 primary school children aged 6-7 years and the levels of nitrogen dioxide (NO2) in the kitchens and bedrooms in their homes. Complete data were collected on about 66% of the population. The children lived in a defined 4 square km area in Middlesbrough, Cleveland, UK. One week average outdoor levels of NO2 varied little over the area (14-24 ppb); The prevalence of respiratory illness was higher in children from gas than electric cooking homes (p approximately or equal to 0.1). Although prevalence was not related to kitchen NO2 levels (range 5-317 ppb) it increased with increasing levels of NO2 in the children's bedrooms in gas cooking homes (range 4-169 ppb, p approximately or equal to 0.1). Symptoms in siblings and parents were not related to kitchen NO2 levels. Lung function was not related to NO2 levels in the kitchen or bedroom. Because of the very low levels of NO2 at which an association with illness was observed and the inconsistency between our results in the UK and those from several studies in the US, it is possible that the NO2 levels were a proxy for some other factor more directly related to respiratory disease such as temperature or humidity.

Air Pollutants↗