La qualité de l'air en France en 1995-96 : Données et Références

Die Luftqualität in Frankreich von 1995-96

Paris

1998

267 S.

Monographie

2-86817-295-4

14133

72551

On the beginning of 1996, the national air quality monitoring equpment is composed of 1214 automatic analysers and samplers managed by 32 local and regional entities approved by the ministry of Environment. They are installed in about 580 monitoring sites: 472 sulfur dioxide, 234 suspended particulates, 221 nitrogen oxides, 53 carbon monoxide, 128 ozone, 44 total hydrocarbons and 62 lead measurement stations. This report provides, for each classical pollutant, an insight into air quality status in the various zones where measurements are being carried out. Information is given about both average and peak levels, exceedances of EU and WHO threshold levels and concentration trend patterns. I - The levels of pollutants released from stationary combustion sources (SO2 taken as a surrogate) keep on declining (figures 0.2 et 0.3). The total SO2 emissions, issued by 72% from combustion, record a 5% decrease between 1994 and 1995 in spite of a slight increase in the power plant exhausts. The total decline in SO2 emissions amounts to 24% between 1990 and 1995. According to the European Environment Agency, the 1995 european sulfur emissions have reached back the 1950 level (about 27 000 kt) after a huge peak of 57 000 kt in the middle of the 70s. As in the previous years, the peak concentrations are recorded in the vicinity of industrial emitters (Fos sur Mer, Carling, Le Havre, Port Jerome, Dunkerque, Lacq...). Only two sites (over 472) don't meet the WHO annual average guideline threshold (50 microg/mß). As for peak levelss, 23% of the sites (22% in 1994) exceed the WHO daily threshold (125 microg/mß which is very close to the EU guide level). The handling of data issued from 162 stations shows that the SO2 immissions keep on decreasing. Between 1990 and 1995 the median of the annual average concentrations has declined by 30%. The trend patterns are not consistent throuhought the zones. While in most sites the concentrations are getting smaller, in Le Havre, Marseille and Strasbourg, the network annual averages have stayed at the same levels between 1994 and 1995. In 1995, the winter meteorology doesn't exhibit any particular cold episode liable to bring about sharp air pollution peaks. II - The immission trend pattern of pollutants issued from traffic is different whether we consider carbon monoxide (CO) or nitrogen oxides (NOx). The urban carbon monoxide and lead immissions keep on dropping (figures 0.2 et 0.3). The CO emissions are issued by 59% from road transport. The passenger car releases amount to 45% of the total CO national emissions. They are declining year after year: 2% drop between 1994 and 1995 and 18% abatment between 1990 and 1995. The reasons of this change are well documented. Both the diesel passenger car and light duty vehicule fleets are expanding. At the beginning of 1996, the diesel motorization involves 26% of in-use private cars (46,5% of new car registrations). During the last 15 years, the proportion of diesel cars has increased by 718% (357% for light duty vehicules). It is worth recalling that a diesel car emits about 20 to 30% less CO than its gazoline counterpart without catalyst. The number of catalyst-equpped gazoline cars is slightly enhancing and involves 20% of the gazoline car fleet (end of 1995). About 75 to 80% of the CO releases are converted into carbon dioxide through the catalyst. On the other hand, the proportion of gazoline cars without catalyst has dropped by 25% between 1990 and 1995. The CO peak immissions are getting lower, in particular in traffic sites. The median of the 98 percentiles decreased by 26% between 1991 and 1995. In 1995, 28% of conurbation traffic sites still record, only during few days per year, exceedances of the WHO 8-h guideline threshold value (10 mg/mß). Due to the increasing consumption of unleaded gazonline and in the wake of the decrease in lead content in the leaded gazoline, the lead immissions have reached low levels. Only one urban site, located near a major throuroufare, doesn't meet the WHO low level threshold (0.5 microg/mß, annual average). The immission trend pattern of suspended particulates concentrations (black smoke) is not very clear. Nevertheless, when we look at the annual average concentrations in concentrations (black smoke) is not very clear. Neverthesless, when we look at the annual average concentrations in conurbations since 1988, we cannot observe, in any case, a decreasing trend. The CORINAIR emission inventory doesn't take into account the suspended particulates. From the conventionnal CITEPA emission inventory, it is not possible to derive any data concerning the fine particule reseases. Therefore, immission and emission data cannot be compared in this field. The nitrogen oxides emissions and peak immission levels are levelling off, after an ongoing decrease for several years (figures 0.2 et 0.3). The NOx emissions are issued by 59% from road transport and by 20% from stationary combustion sources. Private cars and trucks emit respectively 30% and 18% of the total national NOx emissions. The decrease in total NOx emissions, which had been recorded since 1991, seems (provisionally?) interrupted between 1994 and 1995, in spite of the ongoing spread of catalysts in the gazoline car fleet. It seems as if the road transport emissions decrease has been offset by both the slight rise in the power plant emissions and the weak but significant growth in aircraft transport releases. No decline in NO2 average or peak immission concentrations has been recorded between 1994 and 1995. Nevertheless, when we consider the data over the 1988-1995 period of time, the median ot the 98 percentiles of hourly values issued from 36 stations shows a significant reduction of 15% between 1989 and 1995. This trend mainly appears in traffic stations. The peak EU guide value (135 microg/m3, 98 percentile of hourly values) and WHO guidelines (150 microg/m3, max. daily average) are exceeded in several sites (15%), mostly in traffic related stations. III - The slight upward trend of annual average ozone concentrations since 1991 cannot be actually considered as meaningful (figures 26.7 et 26.8). The slight increase (16%) in the median of annual average concentrations since 1991 over 37 stations seems to reach a standstill between 1994 and 1995. The distribution of peak values (median of 98 percentiles of hourly values over 37 sites) doesn't show any clear-cut trend either up or down since 1991. The highest value of the median has been observed in 1995. These evolutions should be handle carefully. The winter meteorology, which is liable to vary widely from one year to another, has a strong influence ont eh immission levels (peaks). The number of sites taken into account is rather low (37 stations) and the involved stations are unevenly spread throughout the country. Due to regional peculiarities, the computed ozone national annual average concentrations may not be actually quite meaningful. New relevant air quality indicators should be set up and validated by the various EU member States. In spite of the fact that the proportion of stations, which exceed the hourly value (180 microg/mß), is similar in 1994 and 1995, the summer 1995 climatology appears mor favourable to the development of smog than the previous summer, in particular in the North and the Ile-de-France region. As in the previous years, nearly all the urban and suburban stations have recorded exceedances of the 8-hours european threshold value (110 microg/mß). Similarly, the great majority of rural and periurban stations have breached the european daily threshold concentration (65 microg/mß).