TARGETS for cutting air pollution to half the level of that of the worst days were dismissed by environmentalists yesterday as unattainable. In the wake of the latest smog alert, the Environmental Protection Department (EPD) said an official target had been set to keep the air pollution index lower than 100 every day and, in the longer term, under 50 on average. The targets had to be met 'as soon as possible', said senior department officer Pang Sik-wing. The Government has just been scraping in under its target this week with readings of 90 on Thursday and up to 89 yesterday. Meeting the targets would prevent acute effects such as eye irritation, wheezing and sore throats, while less than 50 would prevent chronic effects involving the lungs, said Mr Pang. Air was cleaner than had been expected yesterday with an assessment of 'moderate' being issued in the afternoon, compared with a warning for the unhealthiest air on record, which was issued 24 hours earlier. Slower winds reduced dust levels and produced readings from 70 to 89 on the index, down from the forecast of 100, which requires those with respiratory and heart problems to stay indoors. Pollution had worsened in the past few years compared with 10 years ago, said Principal Environmental Protection Officer Tse Chu-wan. The Government was taking a number of initiatives to cut the amount of particulates in the atmosphere. A proposal to convert diesel taxis, minibuses and school buses had run into resistance from operators. Other initiatives had required newly registered cars to run on unleaded petrol, introducing cleaner diesel fuel and proposed regulations to cut dust from building sites. 'If our central measures can go ahead the air quality can improve in the next few years,' said Mr Tse. But Friends of the Earth campaigner Lisa Hopkinson said the air pollution readings threw the Government's seriousness about achieving its goals into doubt. A government review in 1993 found emissions of nitrogen oxides from vehicles would rise 60 per cent by 2001 unless action was taken, she said. 'Without some fairly radical measures, we are going to end up like Bangkok, Seoul and Taipei where people walk around with gas masks,' she said. Better Government co-ordination was needed as projects outside the control of the EPD could affect air pollution such as roads and container ports, which would increase traffic. Mr Pang said five days each year would have registered higher than 100 on the index during the past five years.