I'm worried about our Downtown.

There is every reason to believe that Downtown Pittsburgh will be going straight ahead in coming years. There is construction galore under way or contemplated. It runs from the new PNC building at Fifth and Liberty to the new Penguins arena and related construction at the other end of Fifth Avenue, on the edge of the Hill and Uptown. Point Park University has big plans.

Downtown will include new condominium and apartment buildings. The reservation that some people have expressed about living Downtown -- the absence of a grocery store -- has been dispelled by the opening of the new Rosebud Fine Food Market.

Plans are being studied for Market Square, a perpetual concern in terms of appearance and security. There is reason to believe it will be rendered a stronger center of attraction for Downtown.

But there are still serious problems.

I remember the late Bob O'Connor meeting with the Post-Gazette editorial board when he was running for mayor in 2005. He made us two firm promises: to clean up ("redd up") the city, and to do something about the beggars.

Pittsburgh's Downtown streets remain filthy. The problem is beyond the efforts of the people with the yellow carts and brooms. The people of this town litter with no conscience about its appearance, or the fact that we all live here. I recently had the opportunity to compare Pittsburgh in that regard with New Haven, Conn., and Chicago. Neither city is a model of civic beauty or community responsibility. But the centers of both make Pittsburgh's Downtown look like a horizontal trash can. Why do people choose to throw their litter and gum on the street rather than use the containers spaced around town?

A second problem was underlined when I recently walked nine blocks through Downtown on a weekday morning to find two people sleeping on the sidewalk. One was on Fifth Avenue, the other on Stanwix Street. I am mortified as a citizen that they had been unable to find any other place to sleep, but the effect on anyone seeing them is discouraging at the least.

The third problem is the beggars. I know Downtown well enough to generally be able to track a course that avoids at least the stationary beggars. I also have grown a shell that enables me largely to ignore the ones I can't avoid. But if I know where they are, any civic authorities who had any interest in getting them off the streets would find it easy to do. Instead, they install themselves and ask for money, sometimes even for their animals.

The fourth problem is the most serious. At 6:15 p.m. on a weekday evening, at Fifth Avenue and Smithfield Street, one of the most important crossroads of Downtown, there was a man in his 30s accosting people. Not to beg, I guess, but -- if my case was an example -- to harass and curse them. He yelled at me, insulted me, followed me and tried to provoke me into attacking him, at length. When I ignored him he said I had to turn and pay attention to him and pointed to a bulge in his side pocket which could have been a gun.

I looked at him, thought about taking pre-emptory action, but, mostly because I was late for an appointment, turned my back on him and kept walking while he screamed insults at me at the top of his lungs. I turned on Wood and headed toward the "T" station where there are usually police. There were two police vehicles but no police in sight.

In my life I have run into all manner of things, including drunken soldiers with AK-47s at roadblocks in the Congo and churchyards seeded with mines, so there isn't a whole lot that bothers me. I figured he was bluffing about the gun and that he probably was just drunk, or drugged, or unhinged. (Or maybe he was a Downtown restaurant owner angry about the drink tax.) In fact, he may have been in more danger of injury than I since I was carrying an umbrella with a heavy wooden handle.

But if it had been a child, or perhaps a woman, or someone frail whom he had been threatening, it is distinctly possible that the person would have sworn at that point to never come Downtown again. Forget about the new condos, or the stores, or the restaurants, or the new Market Square, or anything else that anyone could conceivably offer as an incentive for venturing there.

It's not fair to criticize without offering possible remedies. Littering can be stopped with stiff fines. Throw your French fries or your gum on the street and it costs you $100. As for people sleeping on the street, police vans, with personnel from shelters aboard, could patrol at night and systematically pick up people sleeping outside and deposit them at a shelter. They aren't hard to find.

As for the beggars, police should patrol the streets on foot in plain clothes and simply arrest beggars and call for vans to take them away. Anyone who walks Downtown regularly could tell the police exactly where and who they are.

As for the man at Fifth and Smithfield, there need to be some central spots, not too far apart, where there are always police. I suppose people should carry cell phones and dial "911" when they encounter something like that. But I imagine that if I had done that, the man would have attacked me. The best option would to find a police officer near at hand.

It would be nice if Mayor Luke Ravenstahl would be true to the heritage of Bob O'Connor by cleaning up Downtown as it gets its makeover. Otherwise, all of the planning and construction will be for exactly nothing in terms of renewing the heart of Pittsburgh.