IT'S not Cairo's ancient Pharaonic monuments or its intricate Islamic architecture that first strikes many newly arrived visitors.
It's the air: dust in the throat, clouds of black car and bus exhaust, and some days a gray haze that hangs over this swelling metropolis.
The levels of lead and dust in this jam-packed city are among the highest in the world, costing thousands of lives per year, according to a report released last September by the United States Agency for International Development (AID). ''Comparing Environmental Health Risks in Cairo'' is the first report of its kind to assess the health risks of Egypt's pollution.
The biggest hazard facing Egypt today is air pollution, says Salah Hafez, executive director of the official Egyptian Environmental Affairs Agency (EEAA).
An estimated 16,000 deaths -- 10 times the US standard -- can be attributed to dust and particles in Cairo's air, the report states. Largely because of its cement, iron, and steel plants, Cairo has between 4 and 12 times the number of particles in the air compared to the US standard.
Lead in Cairo's air causes an additional 10,000 deaths per year, AID estimates. Children's blood lead levels here are over twice the at-risk level designated for children in the US.
Old, inefficient lead smelters -- factories that make pure lead -- spew particles into the air. And unleaded gasoline is not available in this city of 13 million where many people drive old cars.
The government needs to make unleaded gasoline available and implement laws and incentives to make people switch, says Peter Bjornsen, environmental counselor for the Danish Embassy in Cairo.
Of AID's $815-million 1995 budget, $50 million has been allotted for cleaning Cairo's air.
The agency plans to help the government of Egypt inspect vehicles to remove the biggest polluters from the street.
AID is researching a plan to change bus diesel fuel to natural gas, which is cleaner, and is investigating a scheme to reduce lead levels at smelter factories.
One-quarter of AID's total budget is dedicated to improving Egypt's environment, AID officials estimate. Since the late 1970s, the agency has helped to improve Egypt's dilapidated water and sewer systems.
It has also built more efficient, less polluting power plants.
International pressure and awareness have made Egyptians more concerned about their surroundings in recent years, environmentalists say.
In May 1992, the EEAA with the World Bank's help completed a plan for cleaning Egypt's air, preserving its natural resources and antiquities, and better managing its waste.
The government also passed an environmental law in January 1994. And on Feb. 18, Egyptian Prime Minister Atef Sidki signed into effect regulations to supply environmental standards and administrative systems needed to implement the law.
The Egyptian government has closed most of Cairo's lead smelters. And since 1990, the Ministry of Petroleum has halved the amount of lead in gasoline, according to government estimates.
Higher fuel and electricity prices have prompted Egyptians to use these resources more efficiently.
But cleaning Egypt's air, water, and other resources will not be easy, environmentalists assert. The biggest challenge is raising public awareness, they say. The government needs to make a serious commitment, and industry and the population need to stick to the laws, they add.
And they are hoping cuts won't be made in AID's environmental programs. ''We are depending on AID,'' says Mr. Hafez. AID ''offers an experienced staff, technology, and a sizable investment.''
But with the Republican-controlled Capitol Hill threatening major reductions in US overseas assistance, the AID program could be in danger.
Egypt is an easy target for congressional budget cuts: After Israel, it is the second largest recipient of US foreign aid -- $2 billion annually in US development and military assistance. Israel receives $3 billion.